Conventionally, imaging diagnosis in the medical field indicates that image information obtained by X-ray imaging is output onto an X-ray film, and a doctor or the like observes (interprets) the film image through a radiograph viewer.
In pursuit of ease of observing a region to be diagnosed, a general X-ray film is set to have a contrast corresponding to the density range of 1.0 to about 1.5 D in which the film image can be easily observed. For this reason, if imaging conditions slightly differ from desired conditions, overexposure or underexposure occurs, resulting in imposing adverse effects on imaging diagnosis by image interpretation.
Assume, in particular, that when an object to be imaged (patient or the like) is imaged by X-rays, X-ray imaging is performed for each of a plurality of regions (regions to be diagnosed) constituting the object (divisional imaging). In such a case, since the respective portions to be diagnosed on X-ray films differ in contrast and diagnosis purpose, various attempts are being made to obtain images suitable for imaging diagnosis.
With the recent advances in computers, computers have proliferated into the medical field. This trend has rapidly accelerated in the field of imaging diagnosis as well; there has been an astonishing proliferation of various types of CTs, ultrasound diagnostic equipment, diagnostic equipment using radio isotopes, and the like.
Under the circumstances, there has been developed the concept “comprehensive imaging diagnosis” in which, for example, various types of diagnosing devices are connected through computers to comprehensively diagnose various types of modality images.
Images on X-ray films are essentially analog images, which are used most frequently in imaging diagnosis and regarded important. In spite of this, however, these images have not been fit to the above comprehensive imaging diagnosis and have caused a bottleneck in computerization in the field of imaging diagnosis.
Recently, X-ray imaging apparatuses using solid-stage image sensing devices have been developed, and images (X-ray images) obtained by X-ray imaging have begun to be processed as digital data by using computers. Such techniques allow contrast adjustment of X-ray images that have already been obtained by X-ray imaging and re-imaging due to failure in X-ray imaging.
As X-ray images are digitalized, X-ray images with stabler image quality can be saved, and various kinds of image processing can be done on the basis of the digital data of such X-ray images.
For example, image processing such as temporal difference processing can be performed, in which an X-ray image obtained by preceding X-ray imaging and an X-ray image obtained by current X-ray imaging are digitally positioned to each other, and the difference is obtained. This operation is effective in terms of imaging diagnosis.
Furthermore, with the proliferation of the Internet, various kinds of data processing can be done on the Internet, and the symptom of the development of service type businesses has emerged.
For example, the above temporal difference processing function can be served on the Internet. In addition, for example, medical information (various kinds of medical information including X-ray images) in an intranet can be served on the Internet.
In the above conventional data processing method for the expansion of services on the Internet and the like, the following problems arise.
For example, when medical information and the like inside an intranet (information inside the intranet will also be referred to as “intranet information” hereinafter) are to be served on the Internet, sending intranet information onto the Internet poses a problem in terms of external leakage. For this reason, when a service on the Internet is to be used, external leakage of intranet information must be minimized.
In addition, when a service is provided on the Internet, some medical facilities other than authentic users may illicitly use the service. Authentication of service users may prevent this. However, as the external transmission of intranet information is restricted, it becomes more difficult to authenticate senders.